A combustion engine in a vehicle produces mechanical energy in the form of work which is used to move the vehicle and thermal energy in the form of heat. Excess of heat generated by the engine has to be removed so that the engine is maintained at a constant temperature. To this end, a combustion engine is equipped with a cooling circuit which uses the ambient air to remove the excess of heat produced by the engine.
There is a demand for cooling circuits of increased capacity because of a trend to equip vehicles and especially but not only, industrial vehicles with more powerful and therefore bigger engines. Bigger engines are required to move heavier vehicles and to power additional components such as air conditioning systems, hydraulic devices, alternators for electric equipments etc. Additionally, some vehicles are equipped with pollution control devices such as exhaust gas recycling devices which can have the effect of increasing the heat generated by the engine.
The consequence is that conventional cooling circuits which can include heat exchangers for cooling engine fluids (water, oil or supercharged air), fans and/or pumps have to be dimensioned to remove the heat of currently used big size engines and therefore must be of a substantial size.
This has a considerable impact on the architecture of the vehicle as the vehicle has to be designed to accommodate large cooling packages.
In the case of an industrial vehicle such as a lorry, this means that the vehicle might be taller than desired which is detrimental to aerodynamic drag or to comfort of the vehicle as the cabin has to be higher than desired.
An important point is that the cooling circuit of a vehicle is dimensioned to be effective in a combination of worst case conditions, that is to say conditions combining high ambient temperature, severe route conditions, severe driving conditions and/or high engine load. This is based on the principle that if the cooling circuit is dimensioned to face the worst possible conditions it can therefore operate satisfactorily in any conditions encountered by the vehicle.
It has therefore appeared that there is room to improve the general thermal management of a cooling system in a motorized vehicle.